Concrete substructure caisson.



J. SPELMAN'.

CONCRETE SUBSRUCTURE CAISSON.

APPLICATION FILED FEB.21. 1914.

l ,1 89,2 1 4. Patented June 27, 1916.

2 SHEETS-SHEET 2.

yf-M! lals JAMES sPELMAN, or MONTREAL, QUEBEC, CANADA.

. CONCRETE SUBSTRUCTURE CAISSON.

To all whom t may concern Be it known that I, JAMES SPELMAN, a subject of the King of Great Britain, and resident of the city of Montreal, in the Province of Quebec and Dominion of Canada, have invented certain new and useful Improvements in Concrete Substructure Caissons, of which the following is a full, clear, and exact description.

his invention relates to improvements in concrete or reinforced concrete substructure caissons, and is an improvement on the caisson shown and described in my former U. S. patent application, Ser. No. 803,994, iiled December 1st, 1913.

The objects of this invention are to provide a caisson having a smooth outer or sea wall without sacrificing any of the advantages oflightness and buoyancy arising from the cylindrical structure.

A further object is to provide a caisson which when in place will have greatly reduced toe pressure, and therefore less tendency to tilt outwardly.

A still -further object is to provide a structure which may be constructed with a minimum of expense.

Another object is to provide a structure which when used in tide waters will have practically the same buoyancy at high and low tide.

To accomplish the above objects, I provide a caisson built up of a number of contacted or connected cylinders mounted any suitable number on a heavy base, and provided on what is designed to be the seaward side with a straight wall tangent to the cylinders. This wall forms with the cylinders substantially triangular spaces, which communicate with the water through apertures formed in the base. In the event of two or more rows of cylinders being used in the structure, the spaces between the cylinders are also provided with water inlets through the base. These structures are also formed with the inner row of cylinders lower than the outer for economy of material, and are in addition designed to have only this inner row filled, the outer row of cylinders being provided with suitable apertures for the entrance of water. In this way, the center of gravity is kept well back from the geometric center, so that increased toe pressure and tilting of the structure is prevented.

In the drawings which illustrate the in- Speciiication of Letters Patent.

V the cylindrical Patented June 27, 1916.

Application filed February 21, 1914. Serial N o. 820,238.

vention:-Figure 1 is a front elevation of a caisson designed to be used as a retaining wall. Fig. Qis a plan view ofsame. Fig. 3 is a cross sectional view of the structure in position. Fig. 4 is a plan view of a slightly modified form of structure. Fig. 5 is a cross sectional view of same in position. Fig. 6 is a plan view of a structure embodying certain features of Figs. 2 and 4, and designed for use as a pier.

Referring more particularly to the drawings, 11 designates a base and 12 a plurality of cylinders mounted on the base in one or more rows, said. cylinders being formed integral with the base, which closes the lower ends of the cylinders so that a. cellular structure results. Along one or both sides of the structure, a plain. wall 13 is formed integral with the base and cell walls, and tangent to the latter. This wall, together with the cylindrical walls, forms a plurality of substantially triangular cells 14, while substantially square cells 15 are formed between walls if the structure comprises two or more rows of cells. Owing to the cylindrical forni of the cells, the walls thereof may be made much thinner than would be possible with any other shape, as the walls brace themselves in the well known manner. If the cells 14 and 15 are closed, it will be readily seen that the entire structure is substantially rectangular, and the resistance of the outside cell walls to crushing will be therefore greatly reduced. This is overcome by forming apertures 1G through the base communicating with vthe cells 14 and 15, so that when the structure is floated, as much as possible of the cylindricalI cell walls will be exposed to water pressure. In the case of the wall 13, this is practically a necessity. Vith the water pressure equa-lized on both sides, a comparatively thin wall may be used, while if the pressure was only on the outer side a very much thicker wall would be required.

Referring to Fig. 3, it will be seen that the inner row of cells is much lower than the outer row, with a consequent saving of material and of time in placing the back iilling 17 and cell lilling 18. The outer row of cells remains partially filled or is unfilled with earth or the like after the structure is in place, and is provided with suitable apertures 19 for the admission of water to the cells. The outer row of cells being empty and the inner row filled, it will be readily seen that the center of gravity is considerably inside the geometric center, so that increased pressure on the outer edge of the base and consequent tilting of the structure is avoided. It will be readily seen that a very great advantage arises from admitting water to the outer row of cells. lV hen the structure is placed in tide waters, the increased depth of water at high tide would give considerable buoyancy to the structure, so that filling would be required in the outer row of cells to leep the structure securely in position. At low tide, the buoyancy of the structure would be greatly reduced, so that the downward pressure at the outer edge of the base would be increased. rl`his variation of pressure and buoyancy would subject the structure and the foundation on which it rests to great stress, which might ercntually result in fracture or tilting of the structure. Furthermore, the use of low inside cells enables the filling to partly compensate for its own out thrust.

ln the form shown in Figs. et and 5, it will of course be impossible to utilize the ad- ".*antagcs of filling the inner row of cells, but the water may be admitted into the cells, so as to maintain the downward pressure of the caisson as nearly uniform as possible.

ln F 6 a single section of the caisson is shown designed for use as a pier, the one section shown being the outer end section.

In this form, the cylinders are inclosed by plain walls, the cells formed between the' plain and c 7lindrical walls being open at the bottom for i flotation as previously described. After any of these forms of caisson is in place, it is preferred to fill the cells 14 and 15 with earth, stone, poor concrete or any other desired lling, in order to sink the structure and support the plain walls. The lower portions of the cylindrical cells may also be lled if necessary, and the water admitted through suitable apertures to maintain the downward pressure of the structure uniform. In Fig. 6, elevator shafts 2O are shown formed in the cylindrical cells illus- Copies of this` patent may be obtained for ve cents each, by addressing trating the adaptability of the structure to various purposes.

From the foregoing description, it will be seen that the advantages of the structure are briefly as follows z-A plain outer wall of moderate thickness is obtained without sacrificing the economy of material resulting from the cylindrical cell structure. The two or more rows of cylindrical cells may be used without unbalancing the water pressures on the individual cells. By admitting water to the cells, the downward pressure of the structure at high and low tide is practically the same, while the filling of only the inner rows of cells results in an economy of time and material, and shifts the center of gravity inside the geometric center, so that all tendency to toe pressure and consequent outward inclination is overcome.

Having thus described my invention, what claim is l. A tloatable caisson unit comprising a base, a row of cylindrical cells thereon, and a fiat encircling wall tangent to the cell walls adapted to bind said cells together.

2. A floatable caisson unit comprising a base, a pluralityl of rows of adjacent cylindrical cells thereon, passages through the base between said cells, and an outer encircling wall adapted to bind said cells ton gether and which in turn is braced both transversely and longitudinally by said cells.

3. A floatable caisson unit comprising a base, a plurality of rows of adjacent cylindrical. cells thereon, passages through the base between said cells, and a flat encircling wall tangent to the cell walls adapted to bind said cells together, whereby the cells and walls coperate'to strengthen said unit both longitudinally and transversely.

In witness whereof, l have hereunto set my hand, in the presence of two Witnesses.

JAMES SPELMAN.

Witnesses:

S. R. W. ALLEN, G. M. MORELAND.

the Commissioner of Patenti,

Washington., D. C. 

